Plastic raincoats and plastic ponchos have been available for many years. Very thin sheets of polyethylene have been used for many years to make inexpensive disposable laundry bags and garbage bags have been made from thicker sheet polyethylene. More recently density sheet polyethylene has been used to make inexpensive shopping bags.
Almost every weekend morning at about sunrise, I leave my house for a 4 to 5 hour bicycle ride. If I dress for the first 20 minutes, I have to carry unneeded clothing for the rest of the trip, and if I dress for the rest of the trip, I am cold for the first 20 minutes. Early morning joggers, school children leaving for school at dawn and millions of other early risers have simular problems. What is needed is a garment, preferably low cost, that can be worn for a few minutes then taken off and either disposed of or preferably rolled or folded into a very small package and tucked away in a pocket, pocketbook or brief case for the rest of the day.